Nigella Lawson's former assistants told a London court on November 26 that the chef used cocaine, cannabis and prescription pills daily for a decade.

Celebrity chef Nigella Lawson used drugs for a decade without her then husband Charles Saatchi's knowledge, her former assistants told court.

The allegation came into light during a pre-trial hearing in London where her two former assistants, Francesca and Elisabetta Grillo, were charged with stealing money from her former husband Saatchi over 300,000 pounds to spend on luxury items and holidays, reported Sun online.

Francesca and Elisabetta told the court on November 26 that Lawson used cocaine, cannabis and prescription pills daily for a decade.

The sisters said that Lawson authorised the use of Charles' company credit card for their personal use in exchange for their understanding to keep silence on the issue.

"In a nutshell, we submit that she had a guilty secret from her husband, her then husband. She did not want him to know of her use of cocaine and that is highly relevant to the defense case," Elisabetta's lawyer Anthony Metzer told Isleworth Crown Court.

Prosecuting lawyer Jane Carpenter said, "This is a totally scurrilous account which has been raised by the defence, and the timing is no coincidence at all."